Table of contents

• Table of contents
• Change log
  • 2022.04.30
  • 2022.05.17
• TODO
• Supporting libraries
• Schematic drawing
  • Main control and basic peripherals
    • ESP32-S3 Minimal System
    • ESP32-S3 basic peripherals
  • Screen interface circuit
• PCB drawing
  • ESP32-S3 part
  • Power supply section
  • Interface part
• Appendix: Supported Screen List
  • 1. 40p-0.5-commonly used
    • Type 1
    • Type 2
  • 2. 45p-0.3
  • 3. 51p-0.3
  • 4. 20p-0.5
  • 5. 20p-0.4-double row
  • 5. 40p-0.5-not commonly used

Change log

2022.04.30

• The component information error has been corrected. The previous supplier number has been replaced with the manufacturer number. Supplier number completed. Short contact test points and the like are imported into the BOM. It is too troublesome to change them one by one in the professional version. Remember to delete them when placing orders.
• The network exclusion is changed to 22Ω. ESP32-S3R8 does not transfer to the BOM.
• It seems that oshwhub's md does not support directories.

2022.05.17

• The screen of the 20P is not the touch screen of Daxian, so I am too lazy to change it.
• Uploaded LVGL v8.2.0 routines .
• For the time being, only the SPI interface has been verified. The benchmark can reach 55 frames. The RGB interface is still being adjusted and cannot be adjusted :(. I just found a routine for the 8080 interface and ran it. It is usable, but Xianyu bought that 8080 screen. It’s all bad and I’m speechless.
• Some posed photos:

TODO

• Verification: Verified the watch screen, Wolecon 3.5-inch ST7796S screen, and Xianyu NT35510 screen.
• Program: Only the program for the ST7796S SPI interface is uploaded.
• Other screens will be updated accordingly.

Supporting libraries

LVGL v8.2.0 routines

Schematic drawing

References:

• " ESP32S3 Series Hardware Design Guide "
• " ESP32-S3-WROOM-1 ESP32-S3-WROOM-1U Technical Specification "

Main control and basic peripherals

ESP32-S3 Minimal System

The main control and basic peripherals are shown in the schematic diagram P1. The minimum system is as follows:

The symbol starting with SC (Short Circuit) in the figure is a short contact. Its usage is the same as that of a 0 ohm resistor. You can consider pasting a 0 ohm resistor or directly shorting it with tin. The schematic symbols and packaging are as shown in the figure below. :

The schematic diagram mainly refers to the ESP32-S3-WROOM-1U module schematic diagram. The main features are as follows:

• The main control chip uses ESP32-S3R8.
• The PCB on-board antenna is not used, and the IPEX first-generation antenna interface is used.
• Flash uses two packages: SOIC-8_208mil and WSON-8_8x6mm, which can be easily expanded to 32MB.
• Use more filter capacitors

ESP32-S3 basic peripherals

It mainly consists of filter circuit, reset circuit, power indicator light, GPIO0 button (multiplexed with SCL of I2C bus), Type-C USB interface, external serial port, and 0 ohm resistor.

The corresponding relationship between the GPIO and the screen interface can be clearly seen through the 0 ohm resistor.

There is no built-in USB to serial port module, but the USB analog serial port provided by ESP32-S3 provides JTAG debugging and serial port functions.

System power is provided through the SY8089A1AAC DC-DC step-down.

The symbols starting with the bit number TP (Test Point, test point) are test points; the symbols starting with the bit number NC (None Connect, no connection) are reserved bits, which can usually be left blank.

Screen interface circuit

There are too many to check by yourself, there are labels for which screens are suitable. The PCB in the blue box is not imported.

PCB drawing

The PCB uses a 4-layer board, and the laminated structure is a JLC7628 structure with a finished board thickness of 1.6MM .
The overview is as follows:
Top layer:

Inner layer 2:

Bottom layer:

Inner layer 1 No traces are routed, leaving a complete ground plane.

ESP32-S3 part

Focus on referring to the " ESP32S3 Series Hardware Design Guide ". I have no relevant experience in radio frequency, and the layout is for reference only. Part of the layout of ESP32-S3 is as follows:

main feature:

• The crystal oscillator should be kept as far away from the ESP32-S3 chip as possible, and there should be dense holes around the crystal oscillator to prevent interference.
• The RF surface traces are surrounded by dense holes; 50Ω impedance matching is performed based on the JLC7628 structure; the π-type matching circuit is retained; and truncated lines are added. The impedance is calculated as follows:
  
  
• There are dense holes around the flash, and the signal lines are routed through the inner layer 2 as much as possible, and the ground is wrapped.
  
  
• The power supply is connected in star connection.
  

Other RF references:

• " Onboard PCB Antenna Design Precautions "
• " Detailed explanation of WiFi antenna requirements for PCB layout and structure "
• " Does there need to be clearance underneath the mobile phone antenna used?"》
• " AN928.1: EFR32 Series 1 Layout Design Guide "
• " Microwave Supermarket: Transmission Line Tools "

Power supply section

It mainly includes SY8089's 5V->3V3 DC-DC step-down and MT3540's 5V->24V DC-DC step-up. Stay away from signal lines as much as possible. The power supply trace is 25~50mil. MT3540 Choose whether to weld or not according to personal needs.

Interface part

The layout is as follows:

• When different signal lines cross, ensure that they cross at right angles as much as possible. The inner layer traces are located on inner layer 2, with a complete bottom layer sandwiched between the top traces to reduce interference.
• The inner layer traces (12mil) are slightly thicker than the surface traces (8mil).

Note: I2C touch interface requires your own extension/conversion interface

Appendix: Supported Screen List

• Screen name format:
  manufacturer - size (inch) - number of interface pins - pin spacing - screen type (IPS/NT) - main control chip - interface type
• No manufacturer screen number
• The screens included below are the screens I bought

1. 40p-0.5-commonly used

Type 1

Contains screen:

1. LiangHaoCai-3.5"-40PIN-0.5-IPS-ILI9481-8,16MCU/3,4SPI
2. LiangHaoCai-3.5"-40PIN-0.5-IPS-R61529A-8,16MCU/3SPI
3. Yongda Chuangli-3.5"-40PIN-0.5-NT-ST7796-8,16MCU/3,4SPI
4. Yongda Chuangli-3.5"-40PIN-0.5-NT-ILI9488-8,16MCU/3,4SPI

Interface definition:

Type 2

The main difference from Type 1 : different 37~40 pins, more functions
including screen:

1. Wolecon-3.5"-40PIN-0.5-IPS-ST7796-8,16MCU/3,4SPI/SPI+16RGB

Interface definition:

2. 45p-0.3

Contains screen:

1. LiangHaoCai-3.5"-45PIN-0.3-IPS-R61529A-8,16MCU/16RGB

Interface definition:

3. 51p-0.3

Contains screen:

1. Salted Fish-3.97"-51PIN-0.3-IPS-NT35510-8,16,24MCU/24RGB

Interface definition:

4. 20p-0.5

Contains screen:

1. Large display-2.0"-20PIN-0.5-IPS-ST7789-3,4SPI

Interface definition:

5. 20p-0.4-double row

Contains screen:

1. Laowang-1.3"-16PIN-IPS-ST7789-3,4SPI

Interface definition:

5. 40p-0.5-not commonly used

Contains screen:

1. Large display-3.0"-40PIN-0.5-IPS-S6D04D1-8,16MCU

Interface definition: